This invention relates generally to coin packaging machines of the type operating to wrap a piece of wrapping sheet material around the cylindrical surface of a stack of a specific number of coins and to fold or roll crimp the projecting edges of the wrapping sheet material radially inward at the two ends of the stack thereby to obtained a rigid packaged coin stack. More particularly, the invention relates to novel crimping hooks for fold or roll crimping the wrapping sheet edges in a coin packaging machine.
Each of the crimping hooks used heretofore in coin packaging machines of the above referred to type has comprised a round bar with its working end curved substantially into a semicircular shape of a crook. In the crimping operation, this crook part of the crimping hook is hooked around one of the projecting side edges of the wrapping sheet wrapped around the cylindrical surface of the coin stack, the inner surface of this crook part thereby straddling that edge. Then, as the coin stack thus wrapped continues to rotate, the crimping hook is moved inward toward the coin stack thereby to fold crimp the wrapping sheet edge radially inward into a tight bead which, together with an identical bead simultaneously formed at the other end of the coin stack by the other crimping hook, holds the coin stack and wrapping sheet therearound as a stably rigid package.
In this fold crimping operation with crimping hooks of the above described shape known in the prior art, each projecting edge 1a of the wrapping sheet 1 is first folded inward over itself into a two-layer fold 1b as indicated in FIG. 7(A) of the accompanying drawings briefly described hereinafter. Next, this two-layer fold 1b is further folded inward over itself into a four-layer fold as indicated in FIG. 7(B).
However, in the case where the wrapping sheet material is not a paper but is a sheet of cellophane, a polyethylene, or the like, or in the case of a long projecting length of the wrapping sheet material edges beyond the ends of the coin stack 2, the above described double fold crimping action is not always achieved. More specifically, the extreme edge 1c of the initially folded part 1b of the projecting edge of the wrapping sheet material undergoes a sliding motion to extend inward along the outermost surface of the coin stack 2 as indicated in FIG. 7(C). As a consequence, the second fold crimping is not satisfactorily accomplished, and the resulting fold assumes a feeble, unstable state or a defectively crimped state, whereby a stably and rigidly held state of the coin stack 2 cannot be attained. With the coin package in this state, not only is there a possibility of the package unintentionally becoming undone during its handling after packaging, but the visual appearance of the package is also poor.
Furthermore, an edge crimping mechanism wherein, in order to facilitate the fold crimping action, auxiliary crimping hooks are provided in addition to and in front of the above described fold crimping hooks thereby to assist the folding action at a stage prior to the fold crimping by the fold crimping hooks is known.
These known auxiliary crimping hooks, however, are merely members with working ends curved into a semicircular shape similarly as in the case of the main fold crimping hooks. For this reason, when each projecting edge 1a of the wrapping sheet 1 is first folded inward over itself into a two-layer fold 1b as indicated in FIG. 16(A) and then this two-layer fold 1b is further folded inward over itself, the auxiliary crimping hook presses from the edge of the wrapping sheet material toward the outer coin surface of the coin stack 2 in the case where the wrapping sheet 1 is a material such as cellophane or a polyethylene or in the case where the projecting length of the projecting edge is long. As a consequence, the extreme edge 1c of the initially folded part 1b undergoes a sliding motion to extend along the surface along the outermost coin as indicated in FIG. 16(B), whereby the fold crimping result is unsatisfactory, and not only is there a possibility of the package unintentionally becoming undone during handling after packaging, but the visual appearance of the package is also poor.